The present invention relates to a receiver circuit, a differential signal receiver circuit, an interface circuit, and an electronic instrument.
In recent years, a high-speed serial transfer interface such as low voltage differential signaling (LVDS) has attracted attention as an interface aiming at reducing electromagnetic interference (EMI) noise or the like. In such a high-speed serial transfer interface, data is transferred by causing a transmitter circuit to transmit serialized data using differential signals and causing a receiver circuit to differentially amplify the differential signals.
The receiver circuit includes a differential amplifier circuit for amplifying each signal making up the differential signals. A signal which minutely changes is detected by amplifying the differential voltage between the voltage of each signal and a bias voltage.
In a known differential amplifier circuit of the receiver circuit, when the potential of the transmission line has been determined, the bias voltage is uniquely determined corresponding to the determined potential. Therefore, a voltage generated by a constant voltage generation circuit is provided as the bias voltage in order to provide a stable bias voltage to the receiver circuit. The configuration of such a constant voltage generation circuit is disclosed in JP-A-5-143181, JP-A-5-191167, and JP-A-5-191168, for example.
However, in order to secure the power supply voltage range of the differential amplifier circuit, the bias voltage is set at a high value taking into consideration the manufacturing variation of the constituent element of the differential amplifier circuit. Specifically, the current drive capability of a metal oxide semiconductor (hereinafter abbreviated as “MOS”) transistor of the differential amplifier circuit is increased by increasing the bias voltage. This makes it difficult to operate the differential amplifier circuit at a lower voltage, whereby a higher speed data transfer which requires a low-amplitude signal transmission may not be realized.
As described above, even if a stable constant voltage is supplied as the bias voltage of the differential amplifier circuit which amplifies the received signal, a problem relating to the operation margin of the differential amplifier circuit necessarily occurs when pursuing a high-speed signal transmission. Therefore, it is important to reduce the operation margin of the differential amplifier circuit in order to realize a high-speed signal transmission.
The above problem is common to a high-speed signal transmission using differential signals and a high-speed signal transmission using a single-ended signal.